Ink jet printing systems are known in which a print head defines one or more rows of orifices which receive an electrically conductive recording fluid from a pressurized fluid supply manifold and eject the fluid in rows of parallel streams. Printers using such print heads accomplish graphic reproduction by selectively charging and deflecting the drops in each of the streams and depositing at least some of the drops on a print receiving medium, while others of the drops strike a drop catcher device.
As is obvious to those skilled in the art, the fluid system for a continuous ink jet printer must perform a number of functions. These functions include liquid supply, catch fluid return, startup and shutdown of the print head, and long-term storage. Known fluid systems typically provided electronic control for pressure at the print head, ink temperature during startup, or ink concentration. The control of these functions leads to improved long-term ink jet performance. There are various major components which accomplish these tasks. These components include a dc liquid pump, an ac vacuum pump, and various controls.
Existing ink jet printer systems, such as those described in U.S. Pat. Nos. 4,591,870 and 4,623,897 are much too small for some applications. They operate a print head with 60 jets, whereas it would be desirable to operate a print head with multiply more jets, such as 1024. It would also be desirable to have greater paper throughput in many applications.
It is seen then that there exists a need for a fluid system which can be used with a four inch print head.